This invention relates to a fastener applying device particularly for use in the construction industry, and more specifically to an improved device capable of feeding a cap into a position for penetration by a staple to improve the capability of using staples in use situations previously not considered satisfactory, such as for securing roofing underlayments, and to a fastener applying device having an improved track and feed mechanism for feeding caps to a position for engagement with a fastener such as a staple.
Fastener applying or driving devices known as automatic nailers or staplers are extensively used in the construction industry, although their use for attaching roofing materials to a roof substrate has been severely limited due to the thinness, strength and flexibility characteristics associated with most roofing materials. While automatic staplers and nailers have been used to secure roofing shingles inasmuch as the fastener (i.e. the nail or staple) is ultimately covered by a superimposed shingle, nevertheless these automatic fastening devices have not found wide acceptance or utilization for securing roof underlayments such as tar paper or foam insulating board to the roof substrate due to the thin and/or flexible characteristics of these materials. While automated staplers have in some geographic areas been utilized to secure the tar paper to the roof substrate, this securement provides only a weak attachment, and as such it is imperative that the roofing shingles be immediately applied over the underlayment so as to prevent undesired damage thereto. More conventionally, such underlayments have been secured to the substrate using nails having plastic caps mounted under the head, which nail and cap provides a significantly enlarged gripping area between the cap and substrate so as to permit more secure attachment of the underlayment to the roof substrate. These cap-type nails, however, have traditionally required that they be manually applied, and such is still a very common practice.
Further, when automatic staplers are used for securing either roofing shingles or underlayments to the roofing substrate, the staplers used in the roofing industry traditionally utilize a large staple having about a one inch crown (i.e. width) since such large staple is believed necessary in order to attempt to provide a reasonable securement of the staple over the shingle or underlayment. Staplers using small-size staples are thus not practical for use in roofing applications.
Further, the securement of roofing shingles to the substrate by use of staples is, in most areas within the United States, no longer acceptable since staples have not proven to provide the requisite holding force. Further, staples are also normally not acceptable for securing the underlayment, such as roof felt or vapor wrap (i.e., Tyvap), since the very small holding power of staples readily permits the underlayment to tear through the staple, and hence staples can normally be used only in those situations where the underlayment will be immediately covered by another exterior layer such as roofing shingles.
Other prior attempts to secure underlayment to roofing substrate has, many years ago, involved the use of thin round metal disks (typically called xe2x80x9ctin tabsxe2x80x9d), which tin tabs were typically between about 1⅝ and 2 inch diameter and were manually applied. Initially these tin tabs were individually secured by a plurality of staples, but securing the tin tabs by staples was not commercially acceptable, and most building codes where tin tabs are acceptable now require that the tin tabs be secured using nails. Further, tin tabs continue to be utilized only in a very small number of geographic areas, specifically a few counties in Florida.
In an effort to provide for increased efficiency of securing the underlayment to the roof substrate, the Assignee hereof has developed a fastener applying device which incorporates therein a nailer capable of individually supplying nails from a magazine and individually driving-the nails into the roof so as to permit more efficient and less strenuous securement of the underlayment to the roof substrate. This improved device in addition mounts a basket containing a plurality of plastic caps which are flexibly joined together in side-by-side relationship so as to define a continuous elongate strip which is formed into a spirally-wound reel. The strip of caps withdrawn from the reel is intermittently advanced so as to sequentially supply a cap into the driving zone for penetration by a nail during each driving cycle of the device. Standard nails as disposed within the nail magazine can thus be utilized and the individual nails penetrate respective caps during the nailing operation so as to permit more automated and efficient securement of the underlayments to the roof substrate while at the same time resulting in a cap-type nail being used as the fastener. The improved fastening device described above is illustrated in International Publication WO 99/39878, owned by the Assignee hereof, and the disclosure of this latter publication is incorporated herein by reference. The improved device of this latter publication is also manufactured and sold under license.
While the device capable of feeding and integrating caps and nails, as described above, represents a highly desirable advancement in the construction industry, particularly for securing underlayments to roof substrates, nevertheless there is an ongoing desire to improve the construction and operational simplicity of the device, and to reduce costs associated therewith. For example, the aforementioned device utilizes a loop-like foot structure which closely surrounds and effectively confines the leading cap when in the fastener driving position, and this foot structure is slidably supported on the tool head for significant vertical movement and interconnected with the safety device which must be depressed prior to activation of the device by the manual trigger. This foot arrangement increases the overall complexity of this structure, and of the cap dispensing, and is also a relatively costly structure to manufacture and assemble. The cap feeding arrangement of this device also utilizes a feeding mechanism which engages the caps spaced away from the fastener driving position and, while this device for the most part operates in a satisfactory manner, nevertheless there is concern that this positional relationship may increase the tendency for the advanced caps to buckle or move out of proper position.
Another recognition of the desire to provide an automatic nailer capable of also feeding caps for use in conjunction with the nails is illustrated by U.S. Pat. No. 5,947,362. However, to the best of Applicant""s knowledge, the arrangement illustrated by this latter patent has not been successfully built and operated, either experimentally or commercially.
Accordingly, it is an object of this invention to provide an improved fastener-applying device which is capable of feeding both staples and caps so as to permit individual staples to be driven through respective individual caps so as to permit staples to be used for securement in situations previously not considered feasible, such as for securing thin and/or flexible underlayments to a roofing substrate.
It is also an object of this invention to provide an improved fastener applying device, as aforesaid, which incorporates improved structural and operational simplicity with respect to the track arrangement which feeds caps to the fastener driving region, particularly with respect to the driving and guiding and hold-down structures for the caps, to facilitate the moving of a leading cap into the driving region and the subsequent driving of a fastener therethrough for attachment to a structure such as a roof substrate.
It is a further object of the invention to provide a new and improved fastener applying device, as aforesaid, wherein the device enables the use of significantly smaller staples than conventionally previously felt feasible for use in the roofing industry, and which staples when used in conjunction with the caps provide a significantly increased holding capability with respect to the securement of underlayments to the roofing substrate while permitting such attachment to be carried out in a more automated and time-saving manner and with a higher degree of uniformity.
According to the present invention, there is provided a cap-fastener feeder driver assembly which includes an automatic stapler combined with an automatic cap feeding arrangement so that a disk-like cap is positioned below the staple driver and, upon actuation of the latter, the discharged staple penetrates the cap and fixedly secures the cap-staple combination to the designated wall, such as a roof substrate, to attach other overlayments thereto. The automatic stapler is, by itself, substantially conventional in that it includes a driving head having a transversely projecting handle, and an elongate staple-holding cartridge is secured to and projects transversely from the lower end of the driving head to permit sequential feeding of staples into the guide tube for the reciprocating staple driving member. The cap feeding assembly includes a magazine or basket which contains therein a spirally wound reel of caps which are positioned and joined together in substantially edge-to-edge relationship, with the caps in the preferred embodiment being joined in a continuous strip by an elongate length of adhesive tape. The caps from the reel contained in the magazine are discharged therefrom into a guide track which projects transversely toward and is fixedly supported from the driving head. The guide track has its free or discharge end disposed longitudinally spaced a selected distance from the free end of the driving tool, with the track defining an open region aligned with the tool to accommodate a cap in a driving position for engagement and penetration by a driven staple. The track has appropriate guiding and hold-down structures associated therewith for controlling the positioning of the strip of washers therein, and also has an advancing device movably associated therewith for engaging and forwardly advancing the endmost washer of the strip into the driving position prior to activation of the stapler.
The feeder driver assembly of the invention incorporates preferred features wherein the track, at least adjacent the end thereof where it feeds into the driving region, preferably extends at a substantial angle relative to the feeding direction of the staples in the staple cartridge, which angle is preferably about 45xc2x0, whereby the staple is angularly oriented so as to extend at least partially in the lengthwise direction of the tape which joins the caps together, thereby maximizing the width (i.e. bridge) of the staple while still enabling both legs of the staple to normally effectively penetrate the tape when the staple is driven through the cap. With this arrangement, the leading cap is advanced into the driving zone disposed adjacent the end of the track so as to be aligned with and spaced from the free end of the guide tube for the staple driver. A stop part is provided at the end of the track which, in the preferred embodiment, comprises a pair of sidewardly spaced and substantially parallel legs which straddle the cap located in the driving zone, and which are adapted to define a position of contact engagement with the wall structure to which attachment of the staple is desired. Activation of the trigger on the drive head causes the internal motor to be activated which rapidly extends the staple driving tool and projects the staple outwardly and causes it to penetrate the washer, and the tape thereon, and thereafter penetrate the wall structure so as to fix the staple-cap thereto. The penetration of the tape by the legs of the staple creates two locations which are typically disposed adjacent opposite sides of the tape so as to create weakened zones between the penetrating holes and the tape edges. Initial tearing of the tape may occur due to the slight downward displacement thereof during driving of the staple therethrough. However, when the operator moves the assembly away from the wall structure, the weakened tape sections adjacent the holes formed by the staple legs will tear, if they had not already done so, and the staple will also function as a cutting edge to effect tearing therealong so as to create a tear between the two staple leg holes, thereby effecting severing of the tape on the secured washer from the tape which extends back to the leading washer located in the guide track. When the air motor of the drive head retracts the staple driver, then a driving device cooperates with the lead washer in the guide track and advances same into the driving region defined below the staple driving member.
The present invention also relates to a cap-fastener feeder driver assembly wherein the guide track for feeding a strip of interconnected caps toward a driving zone disposed adjacent a fastener driving element includes a reciprocating feeding device which includes a driving part which preferably engages the leading cap in the strip so as to positively directly push on this cap so as to advance same into the region aligned with the driving tool, with the feeder also preferably directly drivingly engaging the next adjacent cap so as to simultaneously positively drive same forward into the lead position for the next cycle of operation. The guide track arrangement also preferably incorporates a simplified hold-down structure which cooperates directly with the lead cap so as to maintain same in proper position and prevent accidental or undesired upward or rearward movement thereof. This hold-down structure, in combination with the feeding device, and their joint cooperation with the lead cap, ensures accurate and proper feeding of the lead cap so as to minimize misfeeds, misalignment or other undesired and disruptive movements or positions of the caps, and counteracts the return force of the cap feeder.
The present invention has also provided a surprising and unexpected result in that securing a roof underlayment with a plastic cap by means of a staple has proven to provide a significantly greater lateral holding force than would otherwise be expected. In the conventional practice of securing a roof underlayment by means of a plastic cap secured by a nail, a significant lateral holding force is created where the plastic cap, due to its deformation and securement with the nail, engages the underlayment. Applicants have discovered, however, that the present invention utilizing a staple for securing the deformable plastic cap to the underlayment has provided surprisingly good lateral holding force which, while less than that obtained by a nail, is nevertheless far superior to what was expected. This desirable lateral holding force as created by the present invention, however, appears to be optimized when the staple has a crown width in the range of about 35% to about 50% of the cap diameter, so that for a typical one inch diameter plastic cap, a staple crown width of xe2x85x9c to xc2xd inch is believed to provide the best results. While the exact reason for this is not fully understood, nevertheless it is believed that these relationships may provide for more effective compression of the domed portion of the plastic cap, similar to deflection of a spring, so as to optimize the clamping engagement between the cap and the roof underlayment.
Other objects and purposes of the present invention will be apparent to persons familiar with the noted industrial area upon reading the following specification and inspecting the accompanying drawings.